The present invention relates to a process for producing a manufactured item of an at least partly recycled material, as well as to the manufactured item obtained thereby.
It is known that due to the necessity to reduce the environmental impact and to conveniently re-use materials resulting from recovery operations of cast-off items, a great boost has been given to development of the so-called xe2x80x9crecycling industryxe2x80x9d.
In this field, an important work portion is represented by treatment of plastic materials, taking into account their particular chemical composition and the consequent harmful effects that these materials can cause if dispersed in the surrounding environment. In particular, of all the different species of materials obtained from chemical synthesis processes, the so-called composite materials are of particular importance from an environmental and economical point of view.
It is known that production of manufactured items of composite materials is based on the presence in the manufactured item itself of a matrix typically of plastic material in which a mechanically resistant structure is buried which is formed of fibres of material having good mechanical features; these fibres have varying length, orientation and related arrangement depending on the desired application; as mentioned, fibres are inserted in a portion of the binding material mainly of polymeric nature, provided with poor mechanical properties. Obviously, the different planning specifications of the manufactured articles and the necessity to keep the production costs within given limits lead to a great variety of choice as regards both the resistant fibres and the type of structure that these fibres will define as well as finally as regards adoption of the appropriate binding material. In particular, the industrially most used polymeric binding materials can be gathered into two families: thermoplastic resins and thermosetting resins. It is known that thermoplastic resins have a chemical structure enabling the same to melt for an indefinite number of times, whereas thermosetting resins, once polymerized, if they are exposed to high temperatures again, loose their features in an irreversible manner.
In addition to the physico-chemical features of the two families of plastic materials briefly described above, it should be considered the fact that during recycling of the manufactured items made of composite materials, the binding materials of a thermoplastic type have less recovery problems than those of a thermosetting type; on the contrary, for the composite materials having thermosetting binding agents the resin cannot be easily recovered.
In order to obviate the above drawbacks, recycling of manufactured items of a composite material of the thermosetting type is typically made possible by mechanical destruction or crushing of the manufactured item itself, so as to obtain a heterogeneous material made up of broken fibres, portions of fibres forming resin clots and resin granules. Depending on engineering requirements, crushed thermosetting materials of different particle sizes can be obtained.
If recycling of the material thus obtained is wished to be carried out, the material can be used in the different production steps of other composite manufactured items where particular and definite mechanical features are not required. In more detail, if it is necessary to make manufactured articles of composite material, the solution of mixing this recycled material with the fresh binding resin was adopted in the past, so as to help in volume creation while cutting down use of integral and complete resistant fibres and/or fresh binding resin, thereby reaching a great reduction in costs.
Practically the material intended for recycling and coming from a crushing operation is homogeneously distributed within the fresh resin and it too helps in defining the composite material structure, although in a low percentage.
Although they are widely used, the production processes in accordance with the known art briefly described above have some drawbacks.
In fact, due to the particular nature of the thermosetting resin and the intrinsic heterogeneity of the crushed material, the modalities according to which this material is distributed over the different regions of the manufactured item cannot be defined and managed in an accurate manner, above all in connection with a working process for creation of this manufactured item; in particular, in the presently existing production systems there is a tendency to distribute the material to be recycled in a substantially homogeneous manner over the whole manufactured item so that this recycling material affects all the regions of the manufactured item in the same way. Arrangement of the fibres and of all the material resulting from crushing is typically irregular and random so that it is not possible to establish whether the added material to be recycled brings important benefits in terms of increase of the structural capacities of the manufactured item.
These problems are particularly stressed in the construction of manufactured items made of glass fibre in which thermosetting binding agents are generally adopted and for which during the production cycle a step is made necessary in which the glass fibres are chemically treated to ensure adhesion between the fibres themselves and the binding agent.
It is apparent that all fibres for recycling do not possess the same features so that adhesion between the same and the binding agent cannot be ensured always in the same manner; in addition, during addition of said fibres to the new manufactured item they cannot be treated again; this leads to a further factor of impossible definition of the properties of the manufactured item made up of recycled material, because the linking stability between the binding agent and the fibres resulting from crushing is unknown.
Under this situation the technical task underlying the present invention is to conceive a manufactured item of a material at least partly recycled (and a production process to make the same) capable of substantially obviating the mentioned limits.
In particular, the technical task underlying the present invention is to conceive a process for producing a manufactured item of an at least partly recycled material capable of ensuring a real stability in coupling between the binding resin, the resistant fibres and the recycled material, so as to combine the advantageous use of low-cost materials with the substantial determination of the mechanical properties of the new manufactured item.
Another important aim of the present invention is to find a process ensuring a distribution of the recycled material over predetermined regions and according to substantially pre-established arrangements within the new manufactured item.
A further aim of the present invention is to devise a methodology ensuring use of the recycled material in a manner adapted to exploit the mechanical properties of the recycled fibre lengths to some extent.
Within the scope of said technical task it is also an important aim of the invention to devise a process for producing a manufactured article of a material at least partly recycled which can be very easily adapted to any type of volume to be filled, so as to have the greatest operating flexibility.
In addition, a further aim of the present invention is to devise a production process enabling an extensive use of materials from recycling operations, which will bring about advantages in terms of reduction of the environmental impact and re-use of poorly bio-degradable material
A still further aim of the present invention is to devise a process of simple implementation, as well as a manufactured item capable of being handled and/or used without requiring particularly skilled manpower, which will be advantageous as regards facility of use and reduction in costs.
Another aim of the invention is to devise a process and a manufactured item having low manufacturing and installation costs.
The technical task mentioned and the aims specified are substantially achieved by a process for producing a manufactured item of an at least partly recycled material, comprising the following steps: setting a primary continuous layer (2a); setting a filling material (3); wherein said process also comprises at least the further steps of associating a predetermined amount of filling material (3) with said primary continuous layer (2a); and mechanically linking the filling material (3) to the primary continuous layer (2a) to define the manufactured item (1).